The two pedals of a bicycle or the like are normally mounted as shown in U.S. Pat. No. 3,906,811 on a crank assembly comprising a central axis-defining shaft carrying at each end a crank that carries a respective pedal. These cranks normally lie on respective axes perpendicular to the shaft axis, and the pedals are journaled in the outer ends of the cranks for rotation about respective axes parallel to the shaft axis, but diametrically offset therefrom relative to each other.
Normally one of the cranks is cast integrally with the shaft and the other crank is removable. To this end the shaft end for the removable crank is of polygonal section or formed with at least one flat. The removable crank has a correspondingly shaped throughgoing hole of constant cross section into which this one end of the shaft can fit. Furthermore, the removable crank is formed with a cleft or slot that opens into this throughgoing bore, and a bolt extending across this cleft can be used to deform the removable crank and clamp the two sides of this bore tightly against the shaft end.
As it is necessary to form such a cleft by cutting or the like, and thereafter to form a bore for the clamping screw, the fabrication costs of such a crank, which is normally made out of a light metal, are somewhat high. Furthermore it is often impossible to tighten the removable crank adequately, in particular when the flatted shaft end wears somewhat.